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Biomedical subjects

M Kosuge

Publications and source records attributed to M Kosuge.

At least 37 records · Page 2Linked to original sources
PubMed2000

Efficacy of atrioventricular sequential pacing and diastolic mitral regurgitation in patients with intrinsic atrioventricular conduction.

The efficacy of a short atrioventricular (AV) delay in patients with dilated cardiomyopathy has been reported, but there are deleterious effects of right ventricular pacing. Diastolic mitral regurgitation (MR) is observed in patients with elevated left ventricular end-diastolic pressure and can be induced by prolonging the AV delay in patients with DDD pacemakers. The critical PQ interval that induces diastolic MR may represent the upper limit of the optimal PQ interval. The efficacy of AV sequential pacing and diastolic MR were studied in 11 patients (68.3+/-13.7 (SD) years old) with intrinsic AV conduction and with implanted DDD pacemakers. Cardiac output (CO) and pulmonary capillary wedge pressure (PCWP) were measured by Swan-Ganz catheter and transmitral flow was recorded by pulsed Doppler echocardiography. AV delay was prolonged stepwise by 25 ms starting from 65 ms. Pacing rate was fixed at 70-80 beats/min. In 6 of the 11 patients, diastolic MR was observed under atrial pacing and the critical PQ interval for the appearance of diastolic MR was 0.22+/-0.04 s. CO was increased from 3.8+/-0.8 to 4.3+/-0.9 L/min (p<0.05) and PCWP was decreased from 7.5+/-2.8 to 5.5+/-1.6 mmHg (p<0.05) by shortening the AV delay till the diastolic MR disappeared. On the other hand, in 5 of the 11 patients, diastolic MR was not observed, and CO (4.2+/-0.5 to 4.3+/-0.5L/min, ns) and PCWP (5.8+/-4.6 to 5.4+/-3.9 mmHg, ns) were not improved by AV sequential pacing. In conclusion, cardiac function may be improved by AV sequential pacing and setting the AV delay under the critical PQ interval for the appearance of diastolic MR when the diastolic MR is observed. However, AV sequential pacing may be either ineffective or even deleterious for patients in whom diastolic MR is not observed.

Aged↗
PubMed1999

Value of ST-segment elevation pattern in predicting infarct size and left ventricular function at discharge in patients with reperfused acute anterior myocardial infarction.

BACKGROUND: The implication of the shape of ST elevation in the acute phase of myocardial infarction (MI) remains unclear. METHODS AND RESULTS: We examined the relation between the shape of ST elevation and infarct size in 77 patients who had a first acute anterior MI with successful reperfusion within 6 hours from symptom onset. A 12-lead electrocardiogram was recorded immediately before reperfusion confirmed by coronary angiography. The shape of ST elevation in lead V3 was classified into 3 types: concave type (n = 24), straight type (n = 41), and convex type (n = 12). For concave type, straight type, and convex type, a median value of peak creatine kinase was 2287, 4371, and 5322 mU/mL, and left ventricular ejection fraction measured by left ventriculography at discharge (14 days after MI) was 58%, 48%, and 41% (P <.05; concave type versus the other 2 types), respectively. A multivariate logistic regression model demonstrated that the concave type of ST elevation was a strong predicting factor for preserved left ventricular function (left ventricular ejection fraction >/=50% at discharge; odds ratio 6.2, 95% confidence interval 1.6 to 20.8, P =.019). CONCLUSIONS: In patients with reperfused acute anterior MI, left ventricular function was excellent in patients with concave type, intermediate in those with straight type, and relatively poor in those with convex type ST elevation at discharge. This simple classification is useful for predicting left ventricular function at discharge.

Adult↗
PubMed1999

Relationship between atrioventricular delay, QT interval and cardiac function in patients with implanted DDD pacemakers.

QT interval may change when cardiac function is improved by optimizing the atrioventricular the (AV) delay. The relationship between AV delay, QT interval and cardiac function in patients with implanted DDD pacemakers was studied in 12 patients (aged 71+/-12 SD years) with complete or high degree AV block. Cardiac output (CO) was measured using a Swan-Ganz catheter or by continuous Doppler echocardiography. The pacing rate was fixed at 70-80/min to eliminate the influence of heart rate. The AV delay was prolonged stepwise by 30 ms starting from 90 ms. All measurements were performed after 5 min of pacing. When the AV delay was prolonged, the CO and QT interval gradually increased and reached a peak, and then decreased. When the CO was increased from the minimum to the maximum value by optimizing the AV delay, the QT interval was significantly prolonged from 440+/-40 to 456+/-39 ms (P<0.002). The CO increased from 5.5+/-2.5 to 6.0+/-2.5 l x min(-1) (P<0.002) when the AV delay was changed, during which the QT interval was prolonged from the minimum to the maximum value. There was a significant positive correlation between the optimal AV delay at which CO was maximal (161+/-33 ms) and the optimal AV delay predicted from the maximum QT interval (167+/-29 ms, r=0.85, P<0.001). In conclusion, the optimal AV delay can be predicted from the QT interval.

Adult↗
PubMed1999

Prediction of optimal atrioventricular delay in patients with implanted DDD pacemakers.

In patients with an implanted DDD pacemaker (PM), the atrial contribution may be interrupted by too short an atrioventricular (AV) delay, and filling time may be shortened by too long an AV delay. The AV delay at which the end of the A wave on transmitral flow coincides with complete closure of the mitral valve may be optimal. The subjects were 15 patients [70.3+/-12.3 (SD) years old] with an implanted DDD PM. Cardiac output (CO) and pulmonary capillary wedge pressure (PCWP) were measured by Swan-Ganz catheter. Transmitral flow was recorded by pulsed Doppler echocardiography. AV delay was prolonged stepwise by 25 msc. When the AV delay was set at 155+/-26 ms, the end of the A wave coincided with complete closure of the mitral valve. When the AV delay was prolonged 25, 50, 75, and 100 ms from this AV delay, the interval between the end of the A wave and complete closure of mitral the valve was prolonged 16+/-5, 39+/-6, 65+/-4 and 88+/-5 ms, respectively (r = 0.97, P<0.0001) and diastolic mitral regurgitation was observed during this period. Thus, the optimal AV delay may be predicted as follows: the slightly prolonged AV delay minus the interval between the end of the A wave and complete closure of the mitral valve. When the AV delay was set at 215 ms, there was a significant positive correlation between the predicted optimal AV delay (166+/-23 ms) and the optimal AV delay (CO: 161+/-26 msec, r = 0.93, P<0.0001, PCWP: 161+/-28 msec, r = 0.95, P<0.0001). In conclusion, optimal AV delay can be predicted by this simple formula: slightly prolonged AV delay minus the interval between end of A wave and complete closure of mitral valve at the AV delay setting.

Aged↗
PubMed1998

New electrocardiographic criteria for predicting the site of coronary artery occlusion in inferior wall acute myocardial infarction.

In patients with inferior wall acute myocardial infarction (AMI), the site of the culprit lesion is an important determinant of outcome. Patients with right ventricular infarction have a poor prognosis, whereas those with occlusion of the left circumflex coronary artery (LCx) have a good prognosis. Therefore, we assessed whether standard 12-lead electrocardiograms obtained on admission could identify the site of coronary artery occlusion, (i.e., a site proximal to the origin of the right ventricular branch of the right coronary artery [RCA], a site distal to the origin of the right ventricular branch of the RCA, or a site in the LCx). The ratio of ST depression in lead V3 to ST elevation in lead III (V3/III ratio) was evaluated immediately before coronary angiography in 152 patients with a first inferior wall AMI confirmed by coronary angiography within 12 hours after the onset of symptoms. For occlusion of the proximal RCA, distal RCA, and LCx, V3/III ratio was 0.2+/-0.3, 0.8+/-0.5, and 2.5+/-2.5 (p = 0.0001), respectively. The V3/III ratio <0.5 identified proximal RCA occlusion, 0.5 <V3/III ratio < or = 1.2 identified distal RCA occlusion, and 1.2 <V3/III ratio identified LCx occlusion with sensitivities of 91%, 84%, and 84%, and specificities of 91%, 93%, and 95%, respectively. We conclude that the V3/III ratio is useful in predicting the site of coronary artery occlusion in patients with inferior wall AMI.

Adult↗
PubMed1998

Comparison of atrial natriuretic peptide versus nitroglycerin for reducing blood pressure in acute myocardial infarction.

In 10 patients with uncomplicated anterior acute myocardial infarction, within 24 hours after onset, heart rate, plasma renin activity, and the low- to high-frequency power ratio increased and high-frequency power decreased during nitroglycerin infusion; however, both heart rate and plasma renin activity did not change, the low- to high-frequency power ratio decreased, and high-frequency power increased during atrial natriuretic peptide infusion. Atrial natriuretic peptide seems to be more beneficial in its effect on autonomic nervous activity, plasma renin activity, and myocardial oxygen consumption than nitroglycerin for the treatment of anterior acute myocardial infarction.

Aged↗
PubMed1998

Endothelial nitric oxide synthase gene polymorphism and acute myocardial infarction.

Recently a point mutation of guanine to thymine at nucleotide position 1917 in the endothelial nitric oxide synthase (eNOS) gene has been reported to be associated with coronary artery spasm. In addition, a significant association of the 4a/b polymorphism in intron 4 of the eNOS gene with coronary artery disease has been reported. However, the implications of these polymorphisms with respect to acute myocardial infarction (AMI) remain to be established. We conducted a case-control study of 226 patients with AMI and 357 healthy gender- and age-matched control subjects. In the former group, coronary angiograms were evaluated according to angiographic criteria based on the number of diseased vessels (>/=75%) and the number of stenotic lesions (>/=50%). Homozygosity for the Glu-Asp298 polymorphism existed in 5 of 226 patients with AMI (2.2%) but not in any of the 357 control subjects (P=.0085). However, when we evaluated the coronary angiograms of 226 case patients, there was no difference in the number of diseased vessels or the number of stenotic lesions between the patients with this homozygote and those without it. By contrast, there was no evidence of a significant increase in the risk of AMI or the severity of coronary atherosclerosis among individuals with the a/a genotype of the eNOS4a/b polymorphism. Our results imply that patients who are homozygous for the Glu-Asp298 polymorphism may be genetically predisposed to AMI; however, this mutation apparently is not related to the severity of coronary atherosclerosis. Further studies are needed to confirm our results and characterize the molecular mechanisms by which eNOS is involved in susceptibility to AMI.

Case-Control Studies↗
PubMed1998

[Optimal reperfusion therapy in acute myocardial infarction: time to reperfusion and recanalization rate].

Rapid and complete reperfusion is important for the reduction of infarct size and mortality in acute myocardial infarction. The optimum reperfusion therapy with regard to the recanalization rate and the time elapsing between onset and complete reperfusion was evaluated. One hundred fifty-four patients with total occlusion of the infarct-related artery within 6 hours of the onset were classified into four therapy groups: PTCA group (n = 58) undergoing primary percutaneous transluminal coronary angioplasty (PTCA), t-PA-IC group (n = 44) receiving tissue plasminogen activator (t-PA) intracoronary infusion, t-PA-IV group (n = 14) receiving intravenous t-PA infusion, and mt-PA-IV group (n = 38) receiving intravenous mutant t-PA infusion. Although the recanalization rate was high in the PTCA group, there were no differences between the four groups as a supplement to immediate or rescue PTCA. The time elapsing between initiation of thrombolysis and complete reperfusion was shorter in the mt-PA-IV group than in the t-PA-IV group. Assuming the time from hospital arrival to initiation of intravenous thrombolysis was 20 min, the recanalization rate at 60 min after arrival in hospital was higher in the mt-PA-IV group than the PTCA and t-PA-IC groups. Although additional coronary angiography and PTCA may be required to improve the low recanalization rate compared with primary PTCA, intravenous infusion of mutant t-PA was the most promising therapy to achieve early reperfusion.

Aged↗
PubMed1997

Relation of absence of ST reelevation immediately after reperfusion and success of reperfusion with myocardial salvage.

To examine whether resolution in ST elevation without ST reelevation immediately after reperfusion indicates successful reperfusion with myocardial salvage, we studied 40 patients who had an extensive acute myocardial infarction with early reperfusion: 24 patients had ST reelevation and 16 patients had no ST reelevation. Results indicate that (1) in the group with ST reelevation, rapid progression of myocardial damage occurs by reperfusion itself (i.e., reperfusion injury) and (2) in the group without ST reelevation, myocardial damage had already been extensive and irreversible at the time of reperfusion; thus, the absence of ST reelevation is not always a sign of reperfusion with myocardial salvage.

Adult↗
PubMed1997

[Hemodynamic effects of right ventricular outflow pacing].

The effects of right ventricular outflow pacing were studied in 13 patients (mean [+/-SD] 69.8 +/- 8.2 years old). All patients received DDD pacemakers except two patients with implanted VVI pacemakers who had chronic atrial fibrillation. Cardiac output and pulmonary capillary wedge pressure were measured by Swan-Ganz catheter. Pacing rate was fixed at 70-80/min and atrioventricular delay was fixed at 165 msec. When the pacing site was changed from the right ventricular apex to the right ventricular outflow during right ventricular pacing in 11 patients, cardiac output increased from 3.3 +/- 0.6 to 3.4 +/- 0.5 l/min (p < 0.001), and wedge pressure decreased from 9.3 +/- 1.9 to 8.8 +/- 2.0 mmHg (p < 0.05). When the pacing site was changed from the right ventricular apex to the right ventricular outflow during atrioventricular pacing in eight patients, cardiac output increased from 3.9 +/- 0.4 to 4.0 +/- 0.4 l/min (p < 0.05), and wedge pressure decreased from 7.1 +/- 2.3 to 6.6 +/- 2.1 mmHg (p < 0.05). When the pacing site was changed from the right ventricular apex to the right ventricular outflow in seven patients with ejection fraction (EF) greater than 55%, cardiac output increased from 3.6 +/- 0.5 to 3.7 +/- 0.4 l/min (p < 0.05), and in four patients with EF less than 55%, it increased from 2.9 +/- 0.4 to 3.0 +/- 0.4 l/min (p < 0.01). Cardiac function was improved by right ventricular outflow pacing compared to right ventricular apex pacing regardless of the pacing mode or cardiac function.

Aged↗
PubMed1996

Intestinal adenocarcinoma with neuroendocrine cells in a clouded leopard (Neofelis nebulosa).

Adenocarcinoma of the small intestine was found in a 6-year-old clouded leopard. This tumour was characterized by the presence of goblet and neuroendocrine cells. The latter were labelled positively for either serotonin, somatostatin, neurotensin, gastrin or secretin. These neuroendocrine cells were reduced in number in most of the metastatic lesions, including those of the mesentery, diaphragmatic pleura, lungs, liver and heart, and squamous metaplasia was detected in some metastatic sites.

Adenocarcinoma↗
PubMed1996

Alveolar hydatidosis in a gorilla and a ring-tailed lemur in Japan.

Alveolar hydatidosis by Echinococcus multilocularis (Em) infection occurred on a 22-year-old (approx.) male gorilla (Gorilla gorilla) and a 4-year-old female ring-tailed lemur (Lemur catta) in a zoo, in Hokkaido, Japan. Case 1: The gorilla presented neurologic signs in course of nine months and died. Pathologically, alveolar hydatid lesions were found in the liver, the liver-associated lymph nodes, the cerebrum, and the lungs. A protoscolex was found only in one hepatic cyst. Case 2: In the lemur, large masses of hydatide cysts were found on the liver and at the lung-associated lymph nodes. Cysts contained numerous calcareous corpuscles and protoscolices. The lemur appears a favorable intermediate-host for Em. The identification of Em in both cases were confirmed by PCR.

Animals↗
PubMed1996

[Clinical significance of additional ST segment elevation immediately after successful reperfusion in patients with anterior wall acute myocardial infarction].

The clinical significance of additional ST segment elevation immediately after reperfusion in acute myocardial infarction (AMI) is still unclear. The influence of additional ST elevation on myocardial damage was examined in 62 patients with first anterior AMI. All patients had coronary reflow (thrombolysis in myocardial infarction: TIMI grade III) within 6 hours after the onset of infarction and no subsequent reocclusion for at least 14 days. The patients were classified into two groups: group ST (+), 26 patients with additional ST elevation (> or = 5 mm increase in sigma ST in lead V1-V6) immediately after reperfusion, and group ST(-), 36 patients without additional ST elevation. Myocardial damage was estimated by the number of abnormal Q wave before and 1 hour after reperfusion (nQpre and nQpost. There were no significant differences in the elapsed time, ECG indexes before reperfusion and regional wall motion (RWM: SD/chord; SD = standard deviation) in the acute phase and 14 days after the onset between the two groups. Moreover, within each group the patients were classified into two groups on the basis of RWM 14 days after the onset: group A = RWM < -2.5 in group ST (+) (n = 17); group B = RWM > or = -2.5 in group ST(+) (n = 9); group C = RWM < -2.5 in group ST (-) (n = 14); group D = RWM > or = -2.5 in group ST(-) (n = 22). There were no significant differences in the elapsed time between the four groups. nQpre was highest in group C and was lowest in group D (group A: 2.1, group B: 1.9, group C: 4.1, group D: 1.4), and nQpost was highest in group C and group A, and was lowest in group D (group A: 4.1, group B: 2.7, group C: 4.4, group D: 2.0). There was a significant increase in nQ after reperfusion (nQpost-nQpre) in group A and group B, which was greater in group A than in group B. The increase in sigma ST after reperfusion was greater in group A than in group B. There was no significant increase in nQ after reperfusion in group C and in group D, and both nQpre and nQpost were highest in group C, and lowest in group D. Infarct size was larger in group A and in group C than group B and group D, and there was no significant improvement in RWM in group A and in group C. In conclusion, additional ST elevation immediately after reperfusion seems to occur in patients with not so severe myocardial damage before reperfusion, and may reflect reperfusion injury. Additional ST elevation is not observed in patients with preceding extensive myocardial damage which may be irreversible or not still advanced at the time of reperfusion.

Adult↗
PubMed1995

[Clinical significance of late peak formation of creatine kinase in patients with acute anterior myocardial infarction after successful reperfusion].

Generally, the time from the onset of acute myocardial infarction (MI) to peak serum creatine kinase (CK) activity is short in patients with acute MI after successful reperfusion. However, in some patients peak CK is observed more than 16 hours after the onset of acute MI despite successful reperfusion. To elucidate the clinical characteristics of patients with late peak CK, CK activity was examined in 55 patients (mean age: 57.5 +/- 10.2 years) with initial acute anterior MI after successful reperfusion. All patients had coronary reflow (TIMI grade 3) within 6 hours after onset of acute MI and no subsequent reocclusion for at least 14 days. The patients were classified into two groups: group E, 41 patients with peak CK observed within 16 hours of onset of acute MI (mean 8.7 hours), and group L, 14 patients with peak CK observed after more than 16 hours (mean 18.7 hours). Although there were no significant differences in the time elapsed between the two groups, the mean peak CK was significantly lower in group L than in group E (2,179 +/- 861 vs 5,379 +/- 2,569 mU/ml, p < 0.01). Well-developed collateral supplies to the infarcted area before reperfusion were observed more frequently in group L (79% vs 24%, p < 0.01). The sum of ST elevation in all leads before reperfusion was lower in group L (12 +/- 7 vs 20 +/- 12 mm, p < 0.01) and additional ST elevation during reperfusion was not observed in group L (0% vs 56%, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Clinical significance of inverted T-waves during the acute phase of myocardial infarction in patients with myocardial reperfusion].

The relationship between the time course of inverted T-waves during the acute phase and infarct size and left ventricular (LV) function was studied in 46 patients (mean age: 57.3 +/- 9.7 years) with reperfused first anterior wall acute myocardial infarction (MI). All patients had coronary reflow within 6 hrs after the onset of MI and were without subsequent reocclusion for at least 14 days. The T-wave inverted progressively and rapidly with maximum depth between 26 and 60 hrs (mean time: 37.1 +/- 12.4 hrs). A significant correlation was found between the maximum T-wave depth (T-peak) in all patients and peak CPK, left ventricular ejection fraction (LVEF), regional wall motion, % abnormally contracting segment (%ACS), end-diastolic and end-systolic volume indices (EDVI,ESVI) at day 14 after the onset of MI (p < 0.05). T-wave inversion within 24 hrs after onset of MI was observed in 43 patients (93%). There were significant correlations between the depth of T-wave inversion occurring in patients 24 hrs after onset of MI (T24) and peak CPK, LVEF, regional wall motion, % ACS, EDVI, and ESVI at day 14 (p < 0.05). The sensitivity and specificity for patients with EDVI > 87.0 ml/m2 at day 14 increased by more than 20% over normal values, predicted by a T24 of 3.0 mm or less, were 94% and 93%, respectively. The sensitivity and specificity for patients with EF < 40% at day 14 predicted by a T24 of 3.0 mm or less, were 90% and 75%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗